I haven't looked into Hoopla and Libby's policies yet, but I'd be willing to bet they're doing the same. Librarians have traditionally been very concerned with preserving the right to access content and information of all kinds without being monitored. They fought hard (and lost) against the US government being able to collect lists of the books and media users checked out from the library. It's odd to see a librarian advocate for people to use 3rd party services which will do exactly that along with far more invasive tracking.
I'm not just calling you out on this, although some have backed away from these services for various reasons (https://billypenn.com/2021/07/20/free-library-kanopy-movies-...) libraries around the country have embraced services which can track, censor, and put library user's data, privacy, and safety at risk. They advertise and push these services onto library patrons without informing them of the risks and without any mention of what card holders will be giving up by using them. Leaving it to library users to seek out and read through corporate privacy policies full of legal language and weasel wording seems very wrong to me.
In the US, as library card holders, we can't keep our reading lists out of the hands of the state, but we can do more to keep it out of the hands of private for profit companies and data brokers. I'm not saying there's no place for these types of services in libraries (although I'd love to see similar systems developed and operated entirely by library systems instead of 3rd parties), I just wish more libraries were looking out for the privacy of their users and were willing to do more of what they do best: keeping the people informed.